The Sun had no sunspots for two weeks

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Astronomers working for NASA regularly monitor the Sun and note down any unusual patterns. Last month the Solar Dynamics Observatory flagged up something unusual: there were no sunspots for a 15 day period.

NASA scientists regularly scan the Sun for magnetic fields, solar activity (which might damage satellite or solar equipment on Earth), and the star’s sunspots. This information is assessed by the Solar Dynamics Observatory. Between March 7 and March 22, 2017, the observatory noted something that had not previously been observed before: the Sun was completely spotless.

Sunspots are temporary phenomena which occur on the photosphere of the Sun. They visually resemble dark spots, in contrast to the surrounding regions. Sunspots are regions of reduced surface temperature and they are triggered by concentrations of magnetic field flux that inhibit convection. The number of sunspots varies, and they follow an approximate 11-year solar cycle.

Sunspots are important indicators of the Sun transitioning from one phase to another. This is as the Sun goes through a solar maximum or solar minimum event. Solar minimum is the period of least solar activity in the 11 year solar cycle of the sun. During this time, sunspot and solar flare activity diminishes. In contrast, solar maximum is a normal period of greatest solar activity. During solar maximum periods, large numbers of sunspots appear and the sun's irradiance output grows by about 0.07 percent. The increased energy output can impact Earth's global climate and there is an impact upon regional weather patterns.

Back in 2010 the Sun went through a similar, according to Laboratory Roots, but slightly shorter period of time, when no sunspots were recorded. The new pattern, while surprising in terms of the 15 days period, signals that the Sun is about to enter a new solar minimum phase. Whether the 15 days without sunspots signals a different type of solar minimum phase remains to be seen. Researchers predict that the solar minimum will occur between 2019 and 2020.

A solar minimum is a significant part of the Sun’s cycle. Here the Sun enters a temporary period of minimal solar activity. During this period of time the magnetic field slows down and sunspots become less frequent.

This could be the ‘quiet before the storm’ since NASA scientists are also predicting that a 'Maunder Minimum'-like activity from the Sun will occur during the next few decades. According to Dr Mathew Owens from the University of Reading’s meteorology department, this is part of a 300 year long Sun cycle which means: “The magnetic activity of the sun ebbs and flows in predictable cycles, but there is also evidence that it is due to plummet, possibly by the largest amount for 300 years.”

This also carries potential dangers as the scientist predicts: “As the sun becomes less active, sunspots and coronal ejections will become less frequent. However, if a mass ejection did hit the Earth, it could be even more damaging to the electronic devices on which society is now so dependent.”